81 x 9 = 801. What must you do to make the this equation true?

Count the number of balls in picture below:

If Bihan is 10, Anirudha is 20, and Kim and Seal are both 5, but Rikold is 10, how much is Kenniger by the same trend?

What is black when you buy it, red when you use it, and gray when you throw it away?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?

When can we add 2 to 11 and get 1 as the correct answer?

There is one four-digit whole number n, such that the last four digits of n2 are the original number n

What is the next shape from answers A, B, C, and D figure?

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

The Federal bank of London is abducted by the robbers. The head of the robbers asked the cashier to empty their money vault to them and when suddenly cashier got a call from her father. To avoid any suspicion, the robber asked the cashier to pick the call and reply her father in the shortest manner possible.

The cashier told her father "Is there an emergency father, Call me when you are free and I will help you in your furnishing" and then the cashier hung up the phone.

After 10 minutes, police arrived at the crime scene.

How did the police know about the robbery?